Aamunops gen. n.

Type species. Aamunops olmeca sp. n.

Other included species. Aamunops chimpa sp. n., Aamunops misi sp. n., Aamunops noono sp. n.

Etymology. The genus name is taken from the word aamu which means spider in the “Popoluca de la Sierra” dialect. This language belongs to the mixe-zoquean family spoken in the tropical lowlands of the Gulf of Mexico south of Veracruz, a historical region that was part of the Olmec culture. The name is masculine in gender and formed by a combination of the words aamu + nops, the latter a common suffix for several caponiid genera.

Diagnosis. Aamunops gen. n. can be easily distinguished from all caponiine genera by the presence of subsegmented tarsi (Figs. 12, 31, 50, 65). Females differ from all currently known Nopinae except Tarsonops by having an anteromedian membranous receptaculum (Figs. 11, 29, 48). Differs from Tarsonops by the presence of a median sclerotized bifid duct leading to a large, membranous sac (Figs. 11, 30, 49, Sanchez-Ruiz & Brescovit 2015: figs. 29, 47). Males can be distinguished from other Nopinae genera by having a spherical bulb with a sclerotized embolus protruding from the centre (Figs. 7, 27, 46, 64) and by the presence of a hyaline process associated to the seminal duct that ends near the embolus tip (Figs. 16, 37, 55, 68).

Description. Small to medium-sized caponiids. Carapace surface orange, weak patterned; oval, narrowed anteriorly to about a half its maximum width (Figs. 1, 19, 38, 57), pars cephalica in lateral view rounded, with slight depressions opposite intercoxal spaces, pars thoracica flat and short, sloping posteriorly (Figs. 2, 20, 39, 58). Cuticle of carapace reticulated with hexagonal cells, thoracic groove indistinct, carapace covered with long, strong setae mostly concentrated behind eyes, on the clypeal area, around the midline of the pars cephalica and over the depressions (Figs. 1, 38, 41). Two eyes, separated by about a half their diameter and surrounded by a semicircular area of black pigment. Clypeus about twice the diameter of eyes. Cheliceral paturon orange, covered with long, weak setae; prolateral surface with a long median lamina and a white membranous lobe near to the fang base; retrolateral surface with closely spaced stridulatory ridges in both sexes; pick on the prolateral side of palpal femur near to its proximal portion (Brescovit & Sanchez-Ruiz 2016: figs. 4A, F). Endites pale orange, except near the pedipalp joint, convergent along midline but not touching, serrula consisting of a single row of teeth, anterior edge quadrangular, internally with white membranous projections, endite middle section wider and forming an angle of about 90 degrees on the retrolateral margin (Figs. 5, 42), endite posterior margin quadrangular. Labium orange, triangular, fused to sternum, covered with scattered, long setae (Fig. 23). Sternum orange, margin darker, longer than wide, not fused to carapace, sculptured with hexagonal cells, covered with long, stiff setae (Figs. 5, 61); cephalothoracic membranes with sclerotized epimeric extensions above coxae I, II and, III plus IV, the latter shorter; not fused with triangular intercoxal sclerites of sternum, long precoxal triangles on coxae II-IV (arrow Fig. 42). Legs orange, coxae and trochanters pale orange; formula: 4123; setose, without spines; anterior femora and tibiae enlarged; metatarsi entire, with dorsal metatarsal stopper (arrow Fig. 12), anterior legs with crista, occupying 3/4 or less of the ventral surface in males (Figs. 12, 31, 50, 65), almost covering the metatarsus length in females (Figs. 14, 33, 52); membranes separating anterior metatarsi and tarsi with gladius (Figs. 33, 52); all tarsi bi-segmented, proximal segment longer and wider than the distal one, with three claws; paired claws with five to seven teeth (Figs. 18, 53, 67), the most distal largest, unpaired claws short on all legs, hook-shaped, lacking arolium; tibiae, metatarsi and tarsi with trichobothria in a single row; female palpal tarsus elongated, without claw, prolateral and ventral surfaces densely covered with strong setae, dorsal surface with a chemoreceptor patch of short, fine setae. Abdomen dorsum dark gray, lighter ventrally, elongated, setose (Figs. 1, 38); with slightly sclerotized epigastric and post-epigastric scuta (Figs. 3, 40); with two pairs of respiratory spiracles clustered below the epigastric furrow (Figs. 10, 28); anterior spiracles leading to wide, short tubular tracheae branching in numerous, long tracheoles; posterior spiracles each leading to four tracheal trunks, two large, fused at base, that extend anteriorly into the cephalotorax, the others narrowed directed posteriorly and branched in several tracheoles. Six spinnerets in typical caponiid arrangement (Fig. 6, 24); in males, ALS with only one major ampullate gland spigot, PMS with three aciniform gland spigots, PLS with five aciniform gland spigots; in females, ALS with one major ampullate gland and two piriform gland spigots, PMS with one minor ampullate gland and four aciniform gland spigots, PLS with five aciniform gland spigots. Male palpal patella shorter than tibia, cup-shaped; tibia excavated ventrally, with a prolateral brush on its distal portion (Figs. 56, 69); cymbium elongated (Fig. 9), swollen in A. chimpa (Fig. 27), prolateral and ventral surfaces densely covered with strong, long setae, dorsal surface with a chemoreceptor patch of short, fine setae (Figs. 22, 25); bulb globose, spherical, originating from the proximo-ventral region of cymbium (Figs. 7, 44); spermatic duct with a small, hyaline process ending near the embolus tip (Figs. 16, 37, 55, 68); embolus long, short in A. noono, strongly sclerotized, curved, protruding from the center of the bulb, directed ventrally. External female genitalia with anterior plate slightly sclerotized on the postero-median region, posterior plate wide, oval; sclerotized around and between spiracles (Figs. 10, 28, 47); internal genitalia consist of a transverse rigid plate, anterior margin dorsally curved, posterior margin with a median invagination (Figs. 11, 15, 30); membranous anteromedian receptaculum formed by a sclerotized bifid duct that protrudes medially from the plate leading to a large, oval membranous sac-like structure covered with scattered accessory gland openings (Figs. 11, 15, 48).

Distribution. Eastern Mexico (Fig. 83).

Key for the species of Aamunops gen. n.

1 Males .............................................................................................. 2

- Females............................................................................................. 5

2 Long embolus, equal to or longer than palpal tibia, with a hyaline process reaching the tip (Figs. 7, 25, 44).............. 3

- Short embolus, length does no reach a third of the palpal tibia length, with small denticles on the tip, with a minute hyaline process (Figs. 62, 68).................................................................... Aamunops noono

3 Embolus as long as palpal tibia, distal portion bent (Figs. 26, 44)................................................ 4

- Embolus two times longer than palpal tibia, slender, curved (Figs. 7, 16)........................... Aamunops olmeca

4 Thick, rounded embolus tip (Fig. 37); swollen cymbium (Fig. 27)................................. Aamunops chimpa

- Thin, sharpened embolus tip (Fig. 55)......................................................... Aamunops misi

5 Anteromedian receptaculum with a V-shaped sclerotized bifid duct (Fig. 11)........................ Aamunops olmeca

- Anteromedian receptaculum with a T-shaped sclerotized bifid duct.............................................. 6

6 Sclerotized bifid duct long and thin, wide genital opening (Figs. 28, 30)............................ Aamunops chimpa

- Sclerotized bifid duct short and wide, transverse plate with small projections on the postero-median invagination (Fig. 49).......................................................................................... Aamunops misi